%0 Journal Article
%@ 1520-6106
%A Steckel, JA
%A Phung, T
%A Jordan, KD
%A Nachtigall, P
%D 2001
%F pittir:16219
%J Journal of Physical Chemistry B
%N 18
%P 4031 - 4038
%T Concerted Use of Slab and Cluster Models in an ab Initio Study of Hydrogen Desorption from the Si(100) Surface
%U http://d-scholarship-dev.library.pitt.edu/16219/
%V 105
%X Slab and cluster models are used to study H2 desorption from a single dimer of the Si(100)-2 × 1 surface. The cluster models are constructed using geometries obtained from slab-model optimizations. The largest cluster model considered, Si89H62, contains eight surface dimers and gives reaction and activation energies for desorption nearly identical with the slab-model values when the same electronic structure method is used. The barrier for H2 desorption, calculated using the Sisglfe cluster model and the Becke3LYP functional, is 64.3 kcal/mol. When this result is corrected for the effects of basis set expansion and vibrational zero-point energy correction, the barrier decreases to about 61.0 kcal/mol, which is only 4.0 kcal/mol greater than the observed desorption barrier. © 2001 American Chemical Society.